Slide-out filter drawer for a central vacuum system

ABSTRACT

A central vacuum system includes a cylindrical canister with a slide-out filter drawer that can be used either in a filtered or cyclonic vacuum system. The drawer permits servicing the filter without having to otherwise open the canister. The dirtier upstream side of the filter element faces downward to help prevent dust from piling up on the filter element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention generally pertains to central vacuum systems and more particularly to a filter for such a system.

2. Description of Related Art

Typical central vacuum systems comprise a blower or vacuum motor that creates a vacuum within a stationary canister. A network of tubing usually connects the canister to several wall-mounted inlet ports that are installed at various locations throughout a house or building. A flexible hose can connect a portable vacuum tool to any of the inlet ports, so the tool can be used for vacuuming a floor. The vacuum motor draws dust-laden air in series through the tool, through the hose, through the tubing network and into the canister where the dust collects. The canister can be manually opened to empty it periodically.

There are two main types of central vacuum system: cyclonic and filtered. With a cyclonic system, structure within the canister directs the dust-laden air to circulate in a vortex, which employs centrifugal force to help separate the heavier dust particles from the air. A chute directs the separated dust particles to the bottom of the canister where they accumulate for later disposal. The vacuum motor draws the lighter clean air out from within the center of the vortex and discharges the air to atmosphere. Some cyclonic vacuum systems also include a filter, but that is not necessarily always the case.

In comparison, a filtered system includes a filter instead of the vortex-generating structure. The filter blocks the dust particles while allowing clean air to be discharged to atmosphere. If the filter is in the form of a bag, the dust collects in the bag. Otherwise, the dust may simply drop from the filter onto the bottom of the canister. With a filter system, the canister is emptied by first opening the canister and then manually removing the dust from within the bag and/or from the bottom of the canister.

In addition to a canister's main system for separating and collecting the dust, the canister may include a smaller, secondary filter for ensuring that the air is truly clean before being discharged from the canister. This is particularly important in cases where the vacuum motor discharges the air back into the house rather than discharging it outdoors.

Opening the canister of a central vacuum system to dispose of the collected dust is a dirty job. Since the canister typically serves an entire house, the canister can be quite large and bulky, and it can hold a lot of dirt. Thus, it may seem impractical to open a rather large dirty canister just to occasionally clean, inspect, or replace a filter. Thus, there is a need for an easier, cleaner way of accessing the filter.

Various designs have been developed for changing vacuum filters. U.S. Pat. No. 5,230,722, for example, discloses a portable vacuum cleaner whose filter is changed via a slide-out filter tray. Although the filter may be easy to service, it has some limitations.

One, the airflow passes through the filter is a downward direction, which may work for a portable vacuum system. With a central vacuum system, however, the vacuum motor is typically mounted near the top of the canister, so the lower end of the canister is available for collecting dust. Thus, the downward airflow pattern through the filter of the '722 patent is not readily adapted for use on conventional central vacuum systems.

Two, with a downward airflow pattern, dust can pile up or accumulate on top of the filter. The accumulation of dust can obstruct the volume of airflow through the filter, thereby diminishing the overall effectiveness of the vacuum system.

Three, having a drawer opening in a relatively small, portable vacuum cleaner may be fine; however, a drawer penetrating the cylindrical sidewall of a larger diameter central vacuum canister may weaken the canister, which is subject to a potentially crushing pressure differential.

Four, the filter tray of the '722 patent offers no way of creating a seal between an upper surface of the filter element and an upper air passageway leading to the vacuum motor of a conventional central vacuum canister. Without such a seal, air traveling to the vacuum motor could bypass the filter.

Consequently, a need exists for a more convenient way of servicing a secondary filter of a central vacuum system.

SUMMARY OF THE INVENTION

One object of some embodiments of the invention is to provide a cylindrical canister of a central vacuum system with a slide-out filter drawer.

Another object of some embodiments is to provide a central vacuum system with a way of servicing the system's secondary filter without having to interfere with the system's main dust-collecting receptacle.

Another object of some embodiments is to provide the canister of a central vacuum system with a drawer filter that is held in place with the assistance of a vacuum created within the canister.

Another object of some embodiments is to provide a filter and drawer assembly where an upstream surface of the filter faces downward so that dust obstructed by the upstream surface may eventually fall away from the filter and accumulate elsewhere.

Another object of some embodiments is to provide a filter drawer that permits air to pass through and around the drawer, thereby taking greater advantage of the filter's surface area by allowing air to enter both the bottom and side surfaces of the filter.

Another object of some embodiments is to provide a filter drawer that permits air to pass through and around the drawer, yet still reinforces the drawer-penetrated canister of a central vacuum system.

Another object of some embodiments is to provide a slide-out filter drawer for various types of central vacuum systems including, but not limited to, filtered and cyclonic systems.

Another object of some embodiments is to provide a gasket between a filter drawer and an air passageway leading to a vacuum motor.

Another object of some embodiments is tilt a filter element at an angle relative to the horizontal movement of a drawer that supports the filter, so the drawer upon being inserted in the canister wedges the filter sealingly up tight against an air passageway.

One or more of these and/or other objects of the invention are provided by a central vacuum canister that includes a slide-out filter drawer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a vacuum canister and a schematic illustration of the remainder of a central vacuum system, wherein the canister includes a filter drawer shown in its inserted position.

FIG. 2 is a cross-sectional view of the canister of FIG. 1 but showing the filter drawer in its retracted position.

FIG. 3 is a perspective view of a canister with its filter drawer in its retracted position and its associated filter element retracted.

FIG. 4 is a cross-sectional top view taken along line 44 of FIG. 1 with a portion of the filter element cutaway.

FIG. 5 is a cross-sectional view similar to FIG. 1 but showing another type of central vacuum canister.

FIG. 6 is a cross-sectional view similar to FIGS. 1 and 5 but showing yet another type of central vacuum canister.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1-4, a canister 10 for a central vacuum system 12 includes a slide-out filter drawer 14 that facilitate the servicing of a filter element 16.

Central vacuum system 12 comprises a vacuum motor 18 (i.e., a blower) whose fan inlet 20 creates a vacuum in canister 10. A suction pipe 22 connects the vacuum in canister 10 to a network of tubing 24, which leads to several wall-mounted inlet ports 26 that are installed at various locations throughout a house 28 or building. A flexible hose 30 connects a portable vacuum tool 32 to any of the inlet ports 26, so tool 32 can be used for vacuuming a floor 34 or other surfaces.

Vacuum motor 18 draws dust-laden air 36 in series through tool 32, through hose 30, through tubing network 24 and into canister 10 where much of the dust collects within a main filter bag 38. A joint connector 40 enables canister 10 to be manually opened to change the main filter bag or empty the canister periodically. Although, in this example, the air and dust are separated by filtration and the dust is collected within a filter bag, other methods of separation and collection are well within the scope of the invention. After separating dust from the air, vacuum motor 18 discharges cleaner air 36′ through an outlet pipe 42 that exhausts the air to atmosphere.

To ensure that the air discharged to atmosphere is truly clean and to avoid occluding vacuum motor 18 with dust, drawer 14 positions filter element 16 just upstream of fan inlet 20. To accomplish this structurally, a divider 44 divides canister 10 between an upper section 46 and a lower section 48. Divider 44 includes a rim 50 that defines an air passageway 52 leading to fan inlet 20. Drawer 14 holds filter element 16 such that upon inserting drawer 14 into canister 10, a set of tracks 54 guide drawer 14 where the drawer can force an upper surface 56 of filter element 16 up against rim 50. Upper surface 56 may include an annular gasket 58 to ensure a positive seal between rim 50 and filter element 16. Alternatively, annular gasket 58 could be part of or attached to rim 50, whereby a gasket portion of rim 50 would engage an upper surface of filter element 16.

It should be noted that air passing upward through filter element 16 creates a pressure differential across the filter. Although the pressure differential may exert a significant upward force against filter element 16, that force is counteracted by filter element 16 abutting rim 50 of divider 44. Since it is divider 44, and not drawer 14 and track set 54, that provides the reactive force, drawer 14 and track set 54 can be made lighter and less expensive.

To inspect, clean or replace filter element 16, drawer 14 may be manually moved between an inserted position of FIG. 1 and a retracted position of FIG. 2. FIG. 3 shows how easily filter element 16 can be replaced. The new replacement filter element is simply inserted into a pocket 60 of drawer 14.

The actual structure of drawer 14, filter element 16, track set 54, and divider 44 may vary; however, in a currently preferred embodiment, filter element 16 and rim 50 are tilted at an angle 62 (beyond 90-degrees) relative to a longitudinal centerline 64 of canister 10. Angle 62 ensures that filter element 16 is pressed up against rim 50 when drawer 14 is inserted. Angle 62 also aids in removing drawer 14, as filter element 16 does not have to be dragged continuously across rim 50 as drawer 14 is retracted. In a currently preferred embodiment, angle 62 is achieved by having a filter-supporting ledge 66 of drawer 14 being set at angle 62.

In some cases, drawer 14 includes a cover plate 68 that sealingly covers a drawer opening 70 in canister 10. A seal 72 can help close any gaps that may otherwise exist between cover plate 68 and canister 10. A conventional door latch (not shown) and/or canister vacuum acting upon cover plate 68 can help hold cover plate 68 snugly against canister 10 and/or seal 72. It should be appreciated by those of ordinary skill in the art that such a latch or some other closing mechanism may help in sealing the canister so that vacuum motor 18 can initiate a vacuum in the canister. When cover plate 68 is part of drawer 14, rather than being a separate item, the means for holding cover plate 68 shut can be the same means that holds filter element 16 up against rim 50.

The relative translating motion between drawer 14 and track 54 can be accomplished in countless ways. Track 54, for instance, can be a channel in which the drawer's lateral edges 74 slide. Or, the drawer's lateral edges could be in the form of a channel that engages an edge of the tracks. Track 54 could also be an angle or some other structure that provides a ledge upon which drawer 14 slides. The guided translating motion between a drawer and track can also be provided by a linear bearing that may include roller elements.

Filter drawer 14 can help reinforce canister 10 in the area of drawer opening 70. When a vacuum exists inside canister 10, the canister is subjected to an exterior-to-interior pressure differential that applies a compressive force against canister 10. Drawer 14 can help oppose that compressive force by having track set 54 and drawer 14 installed as shown in FIG. 4. More specifically, brackets 76 fasten track set 54 to the inner wall of canister 10 so that brackets 76 and track set 54 transfer the compressive forces (acting on the exterior wall of canister 10) to lateral edges 74 and into drawer 14 itself.

Filter element 16 can be of any suitably porous material, such as foam, pleated paper, etc. To make the most use of the filter element's surface area, drawer 14 defines an opening 78 through which the air can pass prior to passing through a lower surface 80 of filter element 16. In cases where filter element 16 has an outer perimeter 82 that is also porous, the air can pass around drawer 14 through air gaps 84 and enter perimeter 82. Thus, air can pass through both lower surface 80 and perimeter 82 before passing out through an upper surface 86 of filter 16 and entering fan inlet 20.

In some cases, lower section 48 of canister 10 comprises a drawer-supporting section 88 and a dust-collecting section 90, wherein filter element 16 can be contained within drawer-supporting section 88, and dust-collecting section 90 is removable (via fasteners 40) out from underneath drawer-supporting section 88 to dispose of collected dust in the canister.

Slide-out filter drawer 14 can be used in a wide variety of central vacuum systems. FIG. 5, for instance, shows a canister 92 whose main filter 94 is installed above suction pipe 22. De-energizing vacuum system 96 allows some of the dust, which was obstructed by filter 94, to fall back down to the bottom of canister 92, where the dust collects in a pile 98 for later disposal.

Filter drawer 14 can also be used in a cyclonic central vacuum system 100, as shown in FIG. 6. System 100 includes a canister 102 with a vortex-generating cylinder 104. A suction inlet pipe 22′ leading tangentially into canister 102 directs air into a downward circular motion around cylinder 104. Centrifugal force separates the dust from the air by slinging the heavier dust particles against the interior wall of canister 102. A funnel 106 then directs the separated dust to the bottom of canister 102 for later disposal. Once the dust is separated from the air, the cleaner air travels up through a central portion of cylinder 104. From there, the air passes through filter element 16 before vacuum motor 18 discharges the air out through outlet pipe 42.

Although the invention is described with reference to a preferred embodiment, it should be appreciated by those of ordinary skill in the art that various modifications are well within the scope of the invention. Filter element 16, for example, is shown being centered relative to the canister's longitudinal centerline 64; however, the filter element could be radially offset to the centerline to place the filter element closer to the canister's opening 70, thereby shortening the required length of the filter element drawer and the track that supports it. Therefore, the scope of the invention is to be determined by reference to the following claims. 

1. A central vacuum system for moving air, the system comprising: a canister; a divider disposed within the canister to divide the canister between an upper section and a lower section, wherein the divider include a rim that defines an air passageway; a vacuum motor disposed within the upper section of the canister and being adapted to force the air from the lower section upward through the air passageway; a filter drawer translatable within the upper section such that the filter drawer is translatable between an inserted position and a retracted position; and a filter element that includes an upper surface and a lower surface and is supported by the filter drawer such that when the filter drawer is in the inserted position, the upper surface engages the rim of the divider to ensure that the air moving upward from the lower section through the air passageway passes through the filter element before passing through the air passageway, and when the filter drawer is in the retracted position, the filter element can be spaced apart from the canister and the divider, whereby the filter element is readily serviceable.
 2. The central vacuum system of claim 1, further comprising a main filter disposed inside the canister at an upstream location relative to the filter element, wherein the main filter helps clean the air prior to the air passing through the filter element.
 3. The central vacuum system of claim 2, wherein the main filter is a bag.
 4. The central vacuum system of claim 1, further comprising a cyclone apparatus disposed inside the canister at an upstream location relative to the filter element, wherein the cyclone apparatus helps clean the air prior to the air passing through the filter element.
 5. The central vacuum system of claim 1, wherein the filter drawer defines an opening through which the air can pass prior to passing into the lower surface of the filter element, and the filter element includes a porous perimeter through which the air can pass prior to passing out through the upper surface of the filter element, whereby the air can pass through both the lower surface and the porous perimeter before passing through the air passageway.
 6. The central vacuum system of claim 1, wherein the upper surface of the filter element includes an annular gasket that engages the rim when the drawer is in the inserted position.
 7. The central vacuum system of claim 1, wherein the rim includes an annular gasket that engages the upper surface of the filter element when the drawer is in the inserted position.
 8. The central vacuum system of claim 1, wherein the rim lies along a plane that is tilted at an angle relative to a longitudinal centerline of the canister.
 9. The central vacuum system of claim 1, wherein the drawer is upstream of the filter element.
 10. The central vacuum system of claim 1, wherein the lower surface of the filter element is upstream of the upper surface.
 11. The central vacuum system of claim 1, wherein the vacuum motor can create within the canister a vacuum that helps hold the drawer in the inserted position.
 12. The central vacuum system of claim 1, wherein the vacuum motor can create within the canister a vacuum that urges the filter element up against the rim.
 13. The central vacuum system of claim 1, wherein the lower section comprises a drawer-supporting section and a dust-collecting section, wherein the filter element is contained within the drawer-supporting section when the drawer is in the inserted position, and the dust-collecting section is removable out from underneath the drawer-supporting section to provide access to accumulated dust.
 14. A central vacuum system for moving air, the system comprising: a canister; a divider disposed within the canister to divide the canister between an upper section and a lower section, wherein the divider include a rim that defines an air passageway; a vacuum motor disposed within the upper section of the canister and being adapted to draw the air from the lower section upward through the air passageway; a filter drawer translatable within the lower section such that the filter drawer is translatable between an inserted position and a retracted position; and a filter element that includes an upper surface and a lower surface and is supported by the filter drawer such that when the filter drawer is in the inserted position, the upper surface engages the rim of the divider to ensure that the air moving upward from the lower section through the air passageway passes through the filter element before passing through the air passageway, and when the filter drawer is in the retracted position, the filter element can be spaced apart from the canister and the divider, wherein the lower surface of the filter element is upstream of the upper surface and the vacuum motor can create within the canister a vacuum that urges the filter element up against the rim.
 15. The central vacuum system of claim 14, further comprising a main filter disposed inside the canister at an upstream location relative to the filter element, wherein the main filter helps clean the air prior to the air passing through the filter element.
 16. The central vacuum system of claim 14, further comprising a cyclone apparatus disposed inside the canister at an upstream location relative to the filter element, wherein the cyclone apparatus helps clean the air prior to the air passing through the filter element.
 17. The central vacuum system of claim 14, wherein the rim lies along a plane that is tilted at an angle relative to a longitudinal centerline of the canister.
 18. The central vacuum system of claim 14, wherein the drawer is upstream of the filter element.
 19. The central vacuum system of claim 14, wherein the lower section comprises a drawer-supporting section and a dust-collecting section, wherein the filter element is contained within the drawer-supporting section when the drawer is in the inserted position, and the dust-collecting section is removable out from underneath the drawer-supporting section to provide access to accumulated dust.
 20. A central vacuum system for moving air with dust, the system comprising: a cylindrical canister that includes an upper section and a lower section, wherein the lower section comprises a drawer-supporting section and a dust-collecting section, wherein the dust-collecting section is removable out from underneath the drawer-supporting section to provide access to the dust that may have separated from the air and collected in the dust-collecting section; a divider disposed within the canister to divide the canister between the upper section and the lower section, wherein the divider include a rim that defines an air passageway, wherein the rim lies along a plane that is tilted at an angle relative to a longitudinal centerline of the canister; a vacuum motor disposed within the upper section of the canister and being adapted to draw the air from the lower section upward through the air passageway; a filter drawer translatable within the lower section such that the filter drawer is translatable between an inserted position and a retracted position; and a filter element that includes an upper surface and a lower surface and is supported by the filter drawer such that when the filter drawer is in the inserted position, the filter element is contained within the drawer-supporting section with the upper surface engaging the rim of the divider to ensure that the air moving upward from the lower section through the air passageway passes through the filter element before passing through the air passageway, and when the filter drawer is in the retracted position, the filter element can be spaced apart from the canister and the divider, wherein the lower surface of the filter element is upstream of the upper surface and the vacuum motor can create within the canister a vacuum that urges the filter element up against the rim and helps hold the drawer in the inserted position. 